Cognition and motor control as a function of Delta9-THC concentration in serum and oral fluid: limits of impairment

THC and CBD blood and brain concentrations following daily administration to adolescent primates

BACKGROUND

Cannabis availability with high concentrations of Δ-9-tetrahydrocannabinol (THC) and a range of THC to cannabidiol (CBD) ratios has increased in parallel with a rise in daily cannabis consumption by adolescents. Unanswered questions in adolescents include: 1) whether THC blood concentrations and THC metabolites remain stable or change with prolonged daily dosing, 2) whether CBD modulates THC pharmacokinetic properties and alters THC accumulation in brain, 3) whether blood THC levels reflect brain concentrations.

METHODS

In adolescent squirrel monkeys (Saimiri boliviensis), we determined whether a four-month regimen of daily THC (1 mg/kg) or CBD (3 mg/kg) + THC (1 mg/kg) administration (IM) affects THC, THC metabolites, and CBD concentrations in blood or brain.

RESULTS

Blood THC concentrations, THC metabolites and CBD remained stable during chronic treatment. 24 h after the final THC or CBD + THC injection, blood THC and CBD concentrations remained relatively high (THC: 6.0-11 ng/mL; CBD: 9.7-19 ng/mL). THC concentrations in cerebellum and occipital cortex were approximately twice those in blood 24 h after the last dose and did not significantly differ in subjects given THC or CBD + THC.

CONCLUSIONS

In adolescent monkeys, blood levels of THC, its metabolites or CBD remain stable after daily dosing for four months. Our model suggests that any pharmacological interactions between CBD and THC are unlikely to result from CBD modulation of THC pharmacokinetics. Finally, detection of relatively high brain THC concentrations 24 h after the final dose of THC suggests that the prolonged actions of THC may contribute to persistent cognitive and psychomotor disruption after THC- or cannabis-induced euphoria wane.

Orally consumed cannabinoids provide long-lasting relief of allodynia in a mouse model of chronic neuropathic pain

Chronic pain affects a significant percentage of the United States population, and available pain medications like opioids have drawbacks that make long-term use untenable. Cannabinoids show promise in the management of pain, but long-term treatment of pain with cannabinoids has been challenging to implement in preclinical models. We developed a voluntary, gelatin oral self-administration paradigm that allowed male and female mice to consume ∆9-tetrahydrocannabinol, cannabidiol, or morphine ad libitum. Mice stably consumed these gelatins over 3 weeks, with detectable serum levels. Using a real-time gelatin measurement system, we observed that mice consumed gelatin throughout the light and dark cycles, with animals consuming less THC-gelatin than the other gelatin groups. Consumption of all three gelatins reduced measures of allodynia in a chronic, neuropathic sciatic nerve injury model, but tolerance to morphine developed after 1 week while THC or CBD reduced allodynia over three weeks. Hyperalgesia gradually developed after sciatic nerve injury, and by the last day of testing, THC significantly reduced hyperalgesia, with a trend effect of CBD, and no effect of morphine. Mouse vocalizations were recorded throughout the experiment, and mice showed a large increase in ultrasonic, broadband clicks after sciatic nerve injury, which was reversed by THC, CBD, and morphine. This study demonstrates that mice voluntarily consume both cannabinoids and opioids via gelatin, and that cannabinoids provide long-term relief of chronic pain states. In addition, ultrasonic clicks may objectively represent mouse pain status and could be integrated into future pain models.

Examining interactions within the theory of planned behavior in the prediction of intentions to engage in cannabis-related driving behaviors

Objective: As marijuana use becomes more available to college students through increasing legal reform, this paper seeks to examine intentions for driving under the influence of cannabis (DUIC) and riding with a high driver (RWHD) through the lens of the theory of planned behavior (TPB) and assess potential interactions between personal attitudes, subjective norms, perceived behavioral control (PBC), and sex. Participants: Undergraduate college students (N = 311) completed online surveys in September, 2013. Method: Participants self-reported their attitudes toward DUIC, subjective norms, PBC, past DUIC and RWHD, and intentions to DUIC and RWHD. Results: Participants' attitudes toward DUIC, subjective norms, and PBC were strongly associated with intentions to DUIC and RWHD bivariately. In regression models, attitudes and PBC were both positively and significantly related to intentions to DUIC and RWHD. Conclusions: DUIC and RWHD are concerns for college populations. Targeting personal attitudes and perceived behavioral control via interventions may reduce these behaviors.

Rural-urban differences in cannabis detected in fatally injured drivers in the United States

While there is a vast literature on rural and urban differences in substance use, little is known in terms of cannabis positive drug tests among fatally injured drivers. In the present study, we examined rural-urban differences in cannabis detected in fatally-injured drivers. Data were drawn from the 2015-2017 Fatality Analysis Reporting System. Multivariable logistic regression was performed to examine rural-urban differences in the percentage of cannabis detected in fatally-injured drivers. Analyses were stratified by rural-urban classification and sex. A positive cannabis test in fatally-injured drivers was more prevalent in urban locations. Compared to fatally-injured drivers in rural locations, urban drivers had higher odds of a positive test for cannabinoids (aOR: 1.21, 95% CI 1.14-1.28). Non-Hispanic Black drivers had higher odds of testing positive for cannabinoids (aOR: 1.43, 95% CI 1.31-1.55). Those aged at least 25 years had lower odds of a positive test for cannabinoids. Drivers involved in a weekend nighttime crash (aOR: 1.14, 95% CI 1.03-1.26) and weekday nighttime (aOR: 1.15, 95% CI 1.05-1.26) had higher odds of testing positive for cannabinoids compared to drivers involved in a weekend daytime crash. Results showed significant rural-urban differences in the prevalence of cannabis detected in fatally-injured drivers.

Δ9-tetrahydrocannabinol (THC) is present in the body between smoking sessions in occasional non-daily cannabis users

BACKGROUND

THC can be measured in blood up to a month after last intake in heavy cannabis users. The cognitive deficits during abstinence have been hypothesized to be at least in part due to residual THC in brain. To which extent THC accumulation will occur after occasional cannabis use has gained limited attention. We aimed to predict THC-levels between smoking sessions in non-daily as well as daily cannabis users and to compare these predictions with published THC levels.

METHODS

Predictions were based on pharmacokinetic principles on drug accumulation after repeated dosing, applied to different cannabis smoking patterns, using data from a three-compartment model for THC pharmacokinetics and results on the terminal elimination half-life of THC in humans. We searched the literature for THC measurements which could be compared with these predictions. We found no such results from controlled studies of long-term repeated cannabis consumption of known THC amounts. Thirteen published studies contained, however, enough information on cannabis use and results from THC-measurements to make tentative comparisons with the predictions.

RESULTS

The predictions of THC-plasma levels present after different cannabis smoking patterns assuming terminal elimination half-lives of THC of 21.5 h or longer, had some support in published THC levels measured in individuals self-reporting their cannabis consumption. We found no consistent discrepancies between the predictions and reported THC plasma levels after non-daily or daily cannabis use. The predictions indicate that THC might be present in plasma between smoking sessions above usual analytical limits when smoking every third and second day, and at lower levels after once weekly smoking.

CONCLUSIONS

The study indicates that THC might be present continuously even in non-daily smokers at low levels, even if the smoking occasions are separated by a week. This is different from alcohol, where ethanol has disappeared after a day. From a toxicological point of view the persistance of THC in the brain, raises questions whether this should be given more attention as with other toxicological thinking where long-term presence of bioactive substances gives rise to concern. There are some uncertainties in this analysis, and controlled studies on THC-accumulation accompanying different use patterns seem warranted.

[Dependence and Cytotoxicity of Components of Cannabis]

Cannabis use among the younger population in Japan has been steadily increasing. The aim of the present review is to highlight recent knowledge regarding the molecular mechanisms of action and health risks associated with cannabis and synthetic cannabinoid consumption. We investigated the effects of Δ⁹-tetrahydrocannabinol (THC) and synthetic cannabinoids on place conditioning in ICR mice. Both Δ⁹-THC and synthetic cannabinoids produce a significant conditioned place preference. These rewarding effects were completely suppressed by the cannabinoid CB₁ receptor type antagonist AM251. The cytotoxicological effects of Δ⁹-THC and synthetic cannabinoids were also characterized in the limbic forebrain of mice in primary culture in vitro. Δ⁹-THC and synthetic cannabinoids caused cell death in a dose-dependent manner. The rank order of cytotoxicological potency was synthetic cannabinoids>Δ⁹-THC and related to the agonistic activities of the CB₁ receptor. A recent review on the harmful effects of cannabis use in humans reported that behavioral impairments, especially in terms of attention, memory, and complex information-processing ability, can last for many weeks after cessation of cannabis use among heavy users. In addition, cannabis use could be a risk factor for drug dependence and later psychosis among adolescents. The results of animal and human studies suggest that CB₁ receptors play an important role in the expression of harmful effects of cannabis and synthetic cannabinoid use. Moreover, concern regarding increasing concentrations of Δ⁹-THC in cannabis in many countries has been noted, because more potent cannabis may be associated with worse adverse effects.

Marijuana Use and Potential Implications of Marijuana Legalization

Most states in the United States have legalized medical and/or recreational cannabis in response to public demand. Trends in states adopting such legislation demonstrate an increasing prevalence of cannabis use coincident to decreasing perceptions of risk of harm from cannabis products. When providing anticipatory guidance, pediatricians should be prepared to address childhood unintentional ingestion management and prevention, adolescent problem use, and cannabis as an alternative therapy for seizure disorders and other conditions.

Interaction of Cannabis Use and Aging: From Molecule to Mind

Given the aging Baby Boomer generation, changes in cannabis legislation, and the growing acknowledgment of cannabis for its therapeutic potential, it is predicted that cannabis use in the older population will escalate. It is, therefore, important to determine the interaction between the effects of cannabis and aging. The aim of this report is to describe the link between cannabis use and the aging brain. Our review of the literature found few and inconsistent empirical studies that directly address the impact of cannabis use on the aging brain. However, research focused on long-term cannabis use points toward cumulative effects on multimodal systems in the brain that are similarly affected during aging. Specifically, the effects of cannabis and aging converge on overlapping networks in the endocannabinoid, opioid, and dopamine systems that may affect functional decline particularly in the hippocampus and prefrontal cortex, which are critical areas for memory and executive functioning. To conclude, despite the limited current knowledge on the potential interactive effects between cannabis and aging, evidence from the literature suggests that cannabis and aging effects are concurrently present across several neurotransmitter systems. There is a great need for future research to directly test the interactions between cannabis and aging.

Cannabis induced increase in striatal glutamate associated with loss of functional corticostriatal connectivity

Cannabis is the most commonly used illicit drug and is known to alter state of consciousness and impair neurocognitive function. However, the mechanisms underlying these effects have yet to be fully elucidated. Rodent studies suggest that Δ9-tetrahydrocannabinol (THC) activates dopaminergic neurons in the limbic system, subsequently enhancing dopamine, which is implicated in the rewarding effects of cannabis. Additional evidence suggests that THC may act indirectly on dopamine firing by modulating GABA and glutamate release. This double-blind, placebo-controlled study assessed the acute influence of two doses of THC on brain kinetics of glutamate, GABA, and dopamine, in relation to behavioral outcomes, by using magnetic resonance spectroscopy and functional magnetic resonance imaging. Twenty occasional cannabis users received acute doses of cannabis (300 µg/kg THC) and placebo, in one of two dose regimes (full dose and divided dose), during two separate testing days. Administration of THC increased striatal glutamate concentrations, and dopamine as indicated by a reduction in functional connectivity (FC) between the nucleus accumbens (NAc) and cortical areas. Alterations in glutamate and FC were dose dependent and evident in the full dose group where THC serum concentrations exceeded 2 ng/ml at T-max. Average glutamate changes correlated strongly with FC alterations. Additionally, THC induced changes in FC correlated with feelings of subjective high and decreased performance on an attention task. Taken together, this suggests that THC elicits subjective and cognitive alterations via increased striatal dopaminergic activity and loss of corticostriatal connectivity, which is associated with an increase in striatal glutamate.

Positive drug test trends in fatally-injured drivers in the United States from 2007 to 2017

Background

The last two decades have seen tremendous changes in the U.S. environment surrounding drugs. Driving under the influence of drugs is a growing public health hazard. The present study examined trends in drug involvement in fatally-injured drivers in the U.S.

Methods

Data were drawn from the 2007–2017 Fatality Analysis Reporting System. Cochran–Armitage tests were performed to assess the statistical significance of changes in the yearly prevalence of positive drug tests in fatally-injured drivers over time. In addition, analyses were stratified by sex, race, and age.

Results

The yearly prevalence of positive drug tests in fatally-injured drivers increased significantly from 20.7% in 2007 to 30.7% in 2017, with results showing a higher prevalence among males, those aged 21–44, and Whites. The gap between Blacks and Whites narrowed in 2017. There was a decline in the yearly prevalence in all age groups between 2016 and 2017, although the decrease in the 21–44 age group was much smaller than other age groups. Among drivers who tested positive for drugs, 34.6% had a blood alcohol concentration (BAC) above the threshold of per se evidence for impaired driving, and 63% had a BAC below the threshold.

Conclusions

Our results indicate that the overall yearly prevalence of fatally-injured drivers who tested positive for drugs increased significantly from 2007 to 2017, with similar results found for subgroups. Findings further highlight that drugged driving remains a public health priority, and more action is needed to stem this disturbing trend.

Detection of Δ9 THC in oral fluid following vaporized cannabis with varied cannabidiol (CBD) content: An evaluation of two point-of-collection testing devices

Point‐of‐collection testing (POCT) for Δ⁹‐tetrahydrocannabinol (THC) in oral fluid is increasingly used to detect driving under the influence of cannabis (DUIC). However, previous studies have questioned the reliability and accuracy of two commonly used POCT devices, the Securetec DrugWipe^® 5 s (DW5s) and Dräger DrugTest^® 5000 (DT5000). In the current placebo controlled, double‐blind, crossover study we used liquid chromatography‐tandem mass spectrometry (LC–MS/MS) to accurately quantify cannabinoid concentrations in the oral fluid of 14 participants at various timepoints (10, 60, 120, and 180 minutes) following vaporization of 125 mg of THC‐dominant (11% THC; <1% CBD), THC/CBD equivalent (11% THC; 11% CBD) and placebo (<1% THC; <1% CBD) cannabis. At each timepoint, oral fluid was also screened using the DW5s (10 ng/mL THC cut‐off) and DT5000 (10 ng/mL THC cut‐off). LC–MS/MS analysis showed peak oral fluid THC concentrations at the 10 minute timepoint with a rapid decline thereafter. This trajectory did not differ with THC dominant and THC/CBD equivalent cannabis. With a 10 ng/mL confirmatory cut‐off, 5% of DW5s test results were false positives and 16% false negatives. For the DT5000, 10% of test results were false positives and 9% false negatives. Neither the DW5s nor the DT5000 demonstrated the recommended >80% sensitivity, specificity and accuracy. Accuracy was lowest at 60 minutes, when THC concentrations were often close to the screening cut‐off (10 ng/mL). POCT devices can be useful tools in detecting recent cannabis use; however, limitations should be noted, and confirmatory LC–MS/MS quantification of results is strongly advisable.

Correlation of Breath and Blood Δ9-Tetrahydrocannabinol Concentrations and Release Kinetics Following Controlled Administration of Smoked Cannabis

BACKGROUND

Cannabis use results in impaired driving and an increased risk of motor vehicle crashes. Cannabinoid concentrations in blood and other matrices can remain high long after use, prohibiting the differentiation between acute and chronic exposure. Exhaled breath has been proposed as an alternative matrix in which concentrations may more closely correspond to the window of impairment; however, efficient capture and analytically sensitive detection methods are required for measurement.

METHODS

Timed blood and breath samples were collected from 20 volunteers before and after controlled administration of smoked cannabis. Cannabinoid concentrations were measured using LC-MS/MS to determine release kinetics and correlation between the 2 matrices.

RESULTS

Δ9-Tetrahydrocannabinol (THC) was detected in exhaled breath for all individuals at baseline through 3 h after cannabis use. THC concentrations in breath were highest at the 15-min timepoint (median = 17.8 pg/L) and declined to &lt;5% of this concentration in all participants 3 h after smoking. The decay curve kinetics observed for blood and breath were highly correlated within individuals and across the population.

CONCLUSIONS

THC can be reliably detected throughout the presumed 3-h impairment window following controlled administration of smoked cannabis. The findings support breath THC concentrations as representing a physiological process and are correlated to blood concentrations, albeit with a shorter window of detection.

Tetrahydrocannabinol Detection Using Semiconductor-Enriched Single-Walled Carbon Nanotube Chemiresistors

Semiconductor-enriched single-walled carbon nanotubes (s-SWCNTs) have potential for application as a chemiresistor for the detection of breath compounds, including tetrahydrocannabinol (THC), the main psychoactive compound found in the marijuana plant. Herein we show that chemiresistor devices fabricated from s-SWCNT ink using dielectrophoresis can be incorporated into a hand-held breathalyzer with sensitivity toward THC generated from a bubbler containing analytical standard in ethanol and a heated sample evaporator that releases compounds from steel wool. The steel wool was used to capture THC from exhaled marijuana smoke. The generation of the THC from the bubbler and heated breath sample chamber was confirmed using ultraviolet-visible absorption spectroscopy and mass spectrometry, respectively. Enhanced selectivity toward THC over more volatile breath components such as CO₂, water, ethanol, methanol, and acetone was achieved by delaying the sensor reading to allow for the desorption of these compounds from the chemiresistor surface. Additionally, machine learning algorithms were utilized to improve the selective detection of THC with better accuracy at increasing quantities of THC delivered to the chemiresistor.

Cannabis effects on brain structure, function, and cognition: considerations for medical uses of cannabis and its derivatives

Background: Cannabis is the most widely used illicit substance worldwide, and legalization for recreational and medical purposes has substantially increased its availability and use in the United States.Objectives: Decades of research have suggested that recreational cannabis use confers risk for cognitive impairment across various domains, and structural and functional differences in the brain have been linked to early and heavy cannabis use.Methods: With substantial evidence for the role of the endocannabinoid system in neural development and understanding that brain development continues into early adulthood, the rising use of cannabis in adolescents and young adults raises major concerns. Yet some formulations of cannabinoid compounds are FDA-approved for medical uses, including applications in children.Results: Potential effects on the trajectory of brain morphology and cognition, therefore, should be considered. The goal of this review is to update and consolidate relevant findings in order to inform attitudes and public policy regarding the recreational and medical use of cannabis and cannabinoid compounds.Conclusions: The findings point to considerations for age limits and guidelines for use.

Voluntary oral consumption of Δ9-tetrahydrocannabinol by adolescent rats impairs reward-predictive cue behaviors in adulthood

Few preclinical approaches are available to study the health impact of voluntary consumption of edibles containing the psychoactive drug Δ⁹-tetrahydrocannabinol (THC). We developed and validated such approach by measuring voluntary oral consumption of THC-containing gelatin by rats and used it to study if and how THC consumption during adolescence impacts adult behavior. We found that adolescent rats of both sexes consumed enough THC to trigger acute hypothermia, analgesic, and locomotor responses, and that 15 days of access to THC-gelatin in adolescence resulted in the down-regulation of cannabinoid 1 receptors (CB₁Rs) in adulthood in a sex and brain area specific manner. Remarkably, THC consumption by adolescent male rats and not female rats led to impaired Pavlovian reward-predictive cue behaviors in adulthood consistent with a male-specific loss of CB₁R-expressing vGlut-1 synaptic terminals in the ventral tegmental area (VTA). Thus, voluntary oral consumption of THC during adolescence is associated with sex-dependent behavioral impairment in adulthood.

Effect of Smoked Cannabis on Vigilance and Accident Risk Using Simulated Driving in Occasional and Chronic Users and the Pharmacokinetic-Pharmacodynamic Relationship

BACKGROUND

The pharmacokinetic-pharmacodynamic relationship between whole blood δ-9-tetrahydrocannabinol (THC) and driving risk is poorly understood.

METHODS

Fifteen chronic cannabis consumers (1-2 joints/day; CC) and 15 occasional cannabis consumers (1-2 joints/week; OC) of 18 to 34 years of age were included. A pharmacokinetic study was conducted with 12 blood samplings over a 24-h period before and after controlled random inhalation of placebo or 10 mg or 30 mg of THC. THC and metabolites were quantified using LC-MS/MS. Effects on reaction time by psychomotor vigilance tests and driving performance through a York driving simulator were evaluated 7 times. A pharmacokinetic-pharmacodynamic analysis was performed using R software.

RESULTS

Whole blood peak THC was 2 times higher in CC than in OC for a same dose and occurred 5 min after the end of consumption. THC remained detectable only in CC after 24 h. Despite standardized consumption, CC consumed more available THC from each cigarette regardless of dose. Maximal effect for reaction time was dose- and group-dependent and only group-dependent for driving performance, both being decreased and more marked in OC than in CC. These effects were maximal around 5 h after administration, and the duration was longer in OC than in CC. A significant pharmacokinetic-pharmacodynamic relationship was observed only between T _max for blood THC and the duration effect on mean reciprocal reaction time.

CONCLUSIONS

Inhalation from cannabis joints leads to a rapid increase in blood THC with a delayed decrease in vigilance and driving performance, more pronounced and lasting longer in OC than in CC. ClinicalTrials.gov Identifier: NCT02061020.

Neurocognition and Subjective Experience Following Acute Doses of the Synthetic Cannabinoid JWH-018: Responders Versus Nonresponders

Introduction: Synthetic cannabinoid mixtures have been easily accessible for years, leading to the belief that these products were natural and harmless, which contributed to their popularity. Nevertheless, there are many reports of users ending up in hospital due to severe side effects such as tachycardia, aggression, and psychosis. Controlled studies on the effects of synthetic cannabinoids on human performance are lacking. In the present study, we assessed the safety pharmacology of the synthetic cannabinoid JWH-018 after acute administration. Methods: Seventeen healthy cannabis-experienced participants took part in this placebo-controlled, crossover study. Participants inhaled the vapor of JWH-018 (doses ranged between 2 and 6.2 mg) and were subsequently monitored for 12 h, during which vital signs, cognitive performance, and subjective experience were measured. Subjective high scores showed that there is a large variability in the subjective experience of participants. Therefore, a mixed analysis of variance, with "Responder" (i.e., subjective high score >2) as a between-subjects factor and "Drug" as a within-subjects factor (placebo and JWH-018), was used. Results: Serum concentrations of JWH-018 were significantly higher in the responders. Overall, JWH-018 increased heart rate within the first hour and significantly impaired critical tracking and memory performance. Responders to JWH-018 performed more poorly in tests measuring reaction time and showed increased levels of confusion, amnesia, dissociation, derealization, and depersonalization and increased drug liking after JWH-018. Conclusion: JWH-018 administration produced large variability in drug concentrations and subjective experience. Fluctuations in drug delivery probably contributed to the variation in response. JWH-018's impairing effects on cognition and subjective measures were mainly demonstrated in participants who experienced a subjective intoxication of the drug. Lack of control over drug delivery may increase the risk of overdosing in synthetic cannabinoid users.

Combined ∆9-tetrahydrocannabinol and moderate alcohol administration: effects on ingestive behaviors in adolescent male rats

RATIONALE

Whereas co-use of alcohol and marijuana is prevalent in adolescents, the effects of such drug co-exposure on ingestive and cognitive behaviors remain largely unexplored. We hypothesized that co-exposure to alcohol and ∆⁹-tetrahydrocannabinol (THC), the main psychoactive constitute of marijuana, alters feeding behavior and cognition differently from either drug alone.

METHODS

Male rats received daily THC (3-20 mg/kg/day) or oil vehicle through subcutaneous injection or consumption of a cookie with access to saccharin or saccharin-sweetened alcohol during adolescence (P30-45). Barnes maze and sucrose preference tests were applied to assess spatial memory and behavioral flexibility and abstinence-related anhedonia, respectively.

RESULTS

Subcutaneous THC did not affect alcohol intake but dose-dependently increased acute (3 h) chow intake and reduced weight gain. Moderate alcohol consumption reduced the acute hyperphagic effect of subcutaneous THC. By contrast, oral THC at a dose > 5 mg/kg robustly reduced alcohol intake without affecting 3-h chow intake. At this dose, some rats stopped consuming the THC-laced cookies. Furthermore, oral THC reduced weight gain, and co-exposure to alcohol alleviated this effect. Chronic subcutaneous, but not oral, THC reduced sucrose intake during abstinence. Neither treatment impaired cognitive behaviors in the Barnes maze.

CONCLUSION

Moderate alcohol and THC consumption can interact to elicit unique outcomes on ingestive behaviors and energy balance. Importantly, this study established a novel model of voluntary alcohol and THC consumption for studying mechanisms underlying the consequences of adolescent onset co-use of the two drugs.

Marijuana use is associated with alcohol use and consequences across the first 2 years of college

College entry is associated with marijuana initiation, and co-use of alcohol and marijuana is associated with problematic outcomes, including alcohol-related consequences. The present study explored if: (a) use of marijuana on a given day would be associated with greater alcohol use within the same day; (b) use of marijuana within a given week would be associated with increased alcohol-related consequences in that same week; and (c) the association between marijuana use and alcohol consumption and consequences varies across time or by precollege level of problematic alcohol use. Participants (N = 488 college student drinkers, 59% female) completed assessments of marijuana use, alcohol use, and alcohol consequences across 2 years. Analyses revealed: (a) daily marijuana use predicted greater number of daily drinks and estimated breath alcohol concentration; (b) weekly marijuana use predicted more weekly positive and negative alcohol consequences; (c) the effect of daily marijuana use on alcohol use strengthened over time, while the effect of weekly marijuana use on positive alcohol consequences reduced over time; and (d) precollege level of problematic alcohol use moderated the association between daily marijuana and alcohol use and weekly marijuana use and negative consequences. This study provides the first longitudinal evidence of the association between marijuana use and greater alcohol use and consequences in college students. Future research examining event-level measurement of alcohol and marijuana co-use is important for the prevention of alcohol-related consequences. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

The dose-dependent psychomotor effects of intravenous delta-9-tetrahydrocannabinol (Δ9-THC) in humans

BACKGROUND

Binding studies have demonstrated that levels of the cannabinoid receptor type-1 are highest in the basal ganglia and cerebellum, two areas critical for motor control. However, no studies have systematically examined the dose-related effects of intravenous delta-9-tetrahydrocannabinol, the primary cannabinoid receptor type-1 partial agonist in cannabis, on broad domains of psychomotor function in humans.

AIMS

Therefore, three domains of psychomotor function were assessed in former cannabis users (cannabis abstinent for a minimum of three months; n=23) in a three test-day, within-subject, double-blind, randomized, cross-over, and counterbalanced study during which they received intravenous delta-9-tetrahydrocannabinol (placebo, 0.015 mg/kg, and 0.03 mg/kg).

METHODS

Gross motor function was assessed via the Cambridge Neuropsychological Test Automated Battery Motor Screening Task, fine motor control via the Lafayette Instrument Grooved Pegboard task, and motor timing via a Paced Finger-Tapping Task. In addition, the Cambridge Neuropsychological Test Automated Battery Rapid Visual Processing Task was utilized to determine whether delta-9-tetrahydrocannabinol-induced motor deficits were confounded by disruptions in sustained attention.

RESULTS/OUTCOMES

Delta-9-tetrahydrocannabinol resulted in robust dose-dependent deficits in fine motor control (Grooved Pegboard Task) and motor timing (Paced Finger-Tapping Task), while gross motor performance (Motor Screening Task) and sustained attention (Rapid Visual Processing Task) were unimpaired. Interestingly, despite the observed dose-dependent increases in motor impairment and blood levels of delta-9-tetrahydrocannabinol, subjects reported similar levels of intoxication in the two drug conditions.

CONCLUSIONS/INTERPRETATION

These data suggest that while several domains of motor function are disrupted by delta-9-tetrahydrocannabinol, subjective feelings of intoxication are dissociable from cannabinoid-induced psychomotor effects. Results are discussed in terms of the potential neural mechanisms of delta-9-tetrahydrocannabinol in motor structures.

Cannabis use and driving-related performance in young recreational users: a within-subject randomized clinical trial

BACKGROUND

With the legalization of cannabis in Canada, young adults, who are already at risk of automobile crashes, may increase their use of cannabis, which may further increase the risk of crashes. We examined the effects of inhaled cannabis on driving-related performance in healthy 18- to 24-year-old recreational cannabis users.

METHODS

In this within-subject randomized study, participants completed tests in the no-cannabis state and at 1, 3 and 5 hours after inhalation of a standard 100-mg dose of cannabis. We then measured performance (in useful-field-of-view and driving-simulation tests) and self-reported perceptions (driving ability and safety, cannabis effects). Repeated-measures analysis of variance (for cannabis effects on continuous performance measures), Cochran Q tests (for performance-related crash risk and binary complex simulator task scores) and correlational analyses (for self-reported perceptions relative to performance) were employed.

RESULTS

Forty-five participants completed all 180 testing sessions. Significant effects of cannabis (relative to no cannabis) were noted on complex useful-field-of-view tasks at 3 hours (complex divided-attention task: 70 ± 24 ms v. 37 ± 12 ms, 95% confidence intervals [CIs] 28-114 ms v. 29-45 ms, t = -2.98, df = 41, p = 0.005; complex selective-attention task: 102 ± 66 ms v. 64 ± 18 ms, 95% CIs 60-144 ms v. 53-75 ms, t = -2.42, df = 41, p = 0.02) and 5 hours (complex selective-attention task: 82 ± 29 ms v. 61 ± 19 ms, 95% CIs 62-100 ms v. 48-75 ms, t = -2.32, df = 41, p = 0.03) after cannabis use when the tasks were novel (performed in a cannabis state at the first session). Participants were significantly more likely to be classified as having a high crash risk (on the basis of simulator tasks) after cannabis use (χ ² = 13.23, df = 1, p < 0.001, odds ratio 4.31, 95% CI 0.41-45.2) and reported significantly lower perceived driving ability and safety after cannabis use relative to non-use.

INTERPRETATION

Among young recreational cannabis users, a 100-mg dose of cannabis by inhalation had no effect on simple driving-related tasks, but there was significant impairment on complex tasks, especially when these were novel. These effects, along with lower self-perceived driving ability and safety, lasted up to 5 hours after use.

TRIAL REGISTRATION

The trial was registered with Health Canada (NOL [No Objection Letter] no. 215101).

A single dose of cocaine enhances prospective memory performance

BACKGROUND

Prospective memory is the ability to recall intended actions or events at the right time or in the right context. While cannabis is known to impair prospective memory, the acute effect of cocaine is unknown. In addition, it is not clear whether changes in prospective memory represent specific alterations in memory processing or result from more general effects on cognition that spread across multiple domains such as arousal and attention.

AIMS

The main objective of the study was, therefore, to determine whether drug-induced changes in prospective memory are memory specific or associated with more general drug-induced changes in attention and arousal.

METHODS

A placebo-controlled, three-way, cross-over study including 15 regular poly-drug users was set up to test the influence of oral cocaine (300 mg) and vaporised cannabis (300+150 'booster' µg/kg bodyweight) on an event-based prospective memory task. Attentional performance was assessed using a divided attention task and subjective arousal was assessed with the Profile of Mood States questionnaire.

RESULTS

Results showed that cocaine enhanced prospective memory, attention and arousal. Mean performance of prospective memory and attention, as well as levels of arousal were lowest during treatment with cannabis as compared with placebo and cocaine as evinced by a significantly increased trend across treatment conditions. Prospective memory performance was only weakly positively associated to measures of attention and arousal.

CONCLUSION

Together, these results indicate that cocaine enhancement of prospective memory performance cannot be fully explained by parallel changes in arousal and attention levels, and is likely to represent a direct change in the neural network underlying prospective memory.

Examination of the effects of cannabinoid ligands on decision making in a rat gambling task

Although exposure to delta-9-tetrahydrocannabinol (THC) is perceived to be relatively harmless, mounting evidence has begun to show that it is associated with a variety of cognitive deficits, including poor decision making. THC-induced impairments in decision making are thought to be the result of cannabinoid CB1 receptor activation, and although clinical literature suggests that chronic activation via THC contributes to perturbations in decision making, acute CB1 receptor modulation has yielded mixed results. Using an animal model to examine how CB1-specific ligands impact choice biases would provide significant insight as to how recruitment of the endocannabinoid system may influence decision making. Here, we used the rat gambling task (rGT), a validated analogue of the human Iowa Gambling Task, to assess baseline decision making preferences in male Wistar rats. After acquisition rGT performance was measured. Animals were challenged with the CB1 receptor antagonist rimonabant, the partial agonist THC, and the synthetic agonist WIN55,212-2. Animals were also treated acutely with the fatty acid amide hydrolase (FAAH) inhibitor URB597 to selectively upregulate the endocannabinoid anandamide. Blockade of the CB1 receptor produced a trend improvement in decision making in animals who preferred the advantageous task options, yet left choice unaffected in risk-prone rats. Neither CB1 receptor agonist had strong effects on decision making, but a high dose THC decreased premature responses, whereas WIN55,212-2 did the opposite. URB597 did not affect task performance. These results indicate that although chronic CB1 receptor activation may be associated with impaired decision making, acute modulation has modest effects on choice and instead may play a substantive role in regulating impulsive responding.

Interactions between cannabis and schizophrenia in humans and rodents

In this review, we provide an overview of the relationship between cannabis use and the development of schizophrenia, using both animal and human studies. We further discuss the potential neural mechanism that may mediate the relationship between cannabis use and schizophrenia symptoms. We finally provide clinical implications and future studies that can further elucidate the relationship between cannabis and schizophrenia.

Correlation between Blood and Oral Fluid Psychoactive Drug Concentrations and Cognitive Impairment in Driving under the Influence of Drugs

BACKGROUND

The effects of drugs on driving performance should be checked with drug concentration in the brain and at the same time with the evaluation of both the behavioural and neurophysiological effects. The best accessible indicator of this information is the concentration of the drug and/or metabolites in blood and, to a certain extent, oral fluid. We sought to review international studies on correlation between blood and oral fluid drug concentrations, neurological correlates and cognitive impairment in driving under the influence of drugs.

METHODS

Relevant scientific articles were identified from PubMed, Cochrane Central, Scopus, Web of Science, Science Direct, EMBASE up to April 2017.

RESULTS

Up to 2010, no epidemiological studies were available on this matter and International scientists suggested that even minimal amounts of parent drugs in blood and oral fluid could affect driving impairment. More recently, epidemiological data, systematic reviews and meta-analysis on drugged drivers allowed the suggestion of impairment concentration limits for the most common illicit drugs. These values were obtained comparing driving disability induced by psychotropic drugs with that of established blood alcohol limits. Differently from ethyl alcohol where both detection methods and concentration limits have been well established even with inhomogeneity of ranges within different countries, in case of drugs of abuse no official cut-offs have yet been established, nor any standardized analytical protocols.

CONCLUSION

Multiple aspects of driving performance can be differently affected by illicit drugs, and even if for few of them some dose/concentration dependent impairment has been reported, a wider knowledge on concentration/impairment relationship is still missing.

Neurocognition and subjective experience following acute doses of the synthetic cannabinoid JWH-018: a phase 1, placebo-controlled, pilot study

BACKGROUND AND PURPOSE

Synthetic cannabinoids (often sold as Spice or K2) have become a very popular alternative to cannabis due to their easy access and portrayed safety. Controlled studies on the behavioural effects of synthetic cannabinoids are currently lacking, which hampers risk assessments of these compounds.

EXPERIMENTAL APPROACH

This is a first attempt to assess the influence of a synthetic cannabinoid, JWH-018, on neurocognition and subjective experience in humans after controlled administration. JWH-018, 2 and 3 mg, was administered to six healthy cannabis-experienced volunteers in a placebo-controlled, cross-over study following an escalating dosing schedule. Participants were monitored for 12 h after drug administration, and several neurocognitive measures and subjective questionnaires were taken.

KEY RESULTS

Serum concentrations of JWH-018 were highest after the 2 mg dose but generally low after administration of both doses. Both doses of JWH-018 were well tolerated, and no serious side effects were reported. Participants reported feeling more 'high' at 1 and 2 h after administration, particularly after the 2 mg dose. Behavioural impairments also emerged despite the low serum concentrations of JWH-018. The low dose of JWH-018 impaired performance on the tracking, divided attention and stop signal task.

CONCLUSION AND IMPLICATIONS

JWH-018 dosing in the present study resulted in drug concentrations that were generally low and not fully representative of common use. Yet initial impairments of neurocognitive function and subjective feelings of high did emerge despite low levels of JWH-018 in serum. Higher doses are needed to obtain a more representative risk profile of JWH-018.

Continuity of drunk and drugged driving behaviors four years post-college

BACKGROUND

Driving under the influence of alcohol is a leading cause of injury and premature death among young adults, and college-educated individuals are at particularly high risk. Less is known about driving under the influence of other drugs, which is on the rise.

METHOD

This study describes prospective seven-year trends in alcohol and other drug (AOD)-involved driving among a young-adult sample beginning with their second year of college (i.e., Years 2-8), and documents the extent of continuity in such behaviors across time. Originally recruited as incoming first-year students at one large public university, participants (n=1194) were interviewed annually about how frequently they drove while drunk/intoxicated (DWI), after drinking any alcohol (DAD), and/or while under the influence of other drugs (DD). Follow-up rates were high (>75% annually).

RESULTS

Among participants with access to drive a car, annual prevalence peaked in Year 4 (modal age 21) for both DWI (24.3%_wt) and DD (19.1%_wt) and declined significantly thereafter through Year 8 (both ps<0.05). DAD was far more prevalent than DWI or DD, increasing from 40.5%_wt in Year 2 to 66.9%_wt in Year 5, and plateauing thereafter. Among marijuana-using participants, likelihood of DD was consistently greater than the likelihood of DWI among Heavy Episodic and Light-to-Moderate drinkers, and it declined significantly during Years 5-8 (p<0.05).

CONCLUSION

Post-college declines in heavy drinking and DWI prevalence were encouraging but did not necessarily translate to reductions in likelihood of engaging in DWI, depending on drinking pattern. College-educated individuals represent an important target for AOD-involved driving prevention.

Cannabis and cocaine decrease cognitive impulse control and functional corticostriatal connectivity in drug users with low activity DBH genotypes

The dopamine β-hydroxylase (DβH) enzyme transforms dopamine into noradrenaline. We hypothesized that individuals with low activity DBH genotypes (rs1611115 CT/TT) are more sensitive to the influence of cannabis and cocaine on cognitive impulse control and functional connectivity in the limbic ‘reward’ circuit because they experience a drug induced hyperdopaminergic state compared to individuals with high activity DBH genotypes (rs1611115 CC). Regular drug users (N = 122) received acute doses of cannabis (450 μg/kg THC), cocaine HCl 300 mg and placebo. Cognitive impulse control was assessed by means of the Matching Familiar Figures Test (MFFT). Resting state fMRI was measured in a subset of participants to determine functional connectivity between the nucleus accumbens (NAc) and (sub)cortical areas. The influence of cannabis and cocaine on impulsivity and functional connectivity significantly interacted with DBH genotype. Both drugs increased cognitive impulsivity in participants with CT/TT genotypes but not in CC participants. Both drugs also reduced functional connectivity between the NAc and the limbic lobe, prefrontal cortex, striatum and thalamus and primarily in individuals with CT/TT genotypes. Correlational analysis indicated a significant negative association between cognitive impulsivity and functional connectivity in subcortical areas of the brain. It is concluded that interference of cannabis and cocaine with cognitive impulse control and functional corticostriatal connectivity depends on DBH genotype. The present data provide a neural substrate and behavioral mechanism by which drug users can progress to drug seeking and may also offer a rationale for targeted pharmacotherapy in chronic drug users with high risk DBH genotypes.

Toxicological Investigation of Drug-Related Cases in Greece: Interpretation of Analytical Findings

The process of toxicological analysis of postmortem specimens can reveal some special difficulty compared to the clinically derived specimens. Many drugs are not stable and the chemical changes that occur in the specimens, due to the hydrolysis processing, the time passed, the drug metabolism, and matrix effect, even when the postmortem interval is short, may affect the interpretation of the toxicological results. This interpretation may be critical, not only to the thorough investigation of different kind of forensic cases, but also to clinical or other cases as it provides very significant challenges to the scientists. This article reviews (a) particular toxicological issues associated with some toxic substances responsible for common lethal or nonlethal poisonings, such as opiates, cannabis, and cocaine and the vast number of factors that affect drug concentration; and (b) focuses on toxicological issues associated with the analytical findings of certain postmortem specimens. The toxic substances cited in the present paper are the most commonly found in forensic cases in Greece. The investigation of these drug-related deaths has revealed that heroin, alone or in combination with other psychoactive substances, such as cannabis and cocaine, is the main drug involved in these deaths.

Cannabis use in people with Parkinson's disease and Multiple Sclerosis: A web-based investigation

OBJECTIVES

Cannabis has been used for medicinal purpose for thousands of years; however the positive and negative effects of cannabis use in Parkinson's disease (PD) and Multiple Sclerosis (MS) are mostly unknown. Our aim was to assess cannabis use in PD and MS and compare results of self-reported assessments of neurological disability between current cannabis users and non-users.

METHODS

An anonymous web-based survey was hosted on the Michael J. Fox Foundation and the National Multiple Sclerosis Society webpages from 15 February to 15 October 2016. The survey collected demographic and cannabis use information, and used standardized questionnaires to assess neurological function, fatigue, balance, and physical activity participation. Analysis of variance and chi-square tests were used for the analysis.

RESULTS

The survey was viewed 801 times, and 595 participants were in the final data set. Seventy-six percent and 24% of the respondents reported PD and MS respectively. Current users reported high efficacy of cannabis, 6.4 (SD 1.8) on a scale from 0 to 7 and 59% reported reducing prescription medication since beginning cannabis use. Current cannabis users were younger and less likely to be classified as obese (P < 0.035). Cannabis users reported lower levels of disability, specifically in domains of mood, memory, and fatigue (P<0.040).

CONCLUSIONS

Cannabis may have positive impacts on mood, memory, fatigue, and obesity status in people with PD and MS. Further studies using clinically and longitudinally assessed measurements of these domains are needed to establish if these associations are causal and determine the long-term benefits and consequences of cannabis use in people with PD and MS.

THC and CBD in blood samples and seizures in Norway: Does CBD affect THC-induced impairment in apprehended subjects?

BACKGROUND AND AIMS

Several publications have suggested increasing cannabis potency over the last decade, which, together with lower amounts of cannabidiol (CBD), could contribute to an increase in adverse effects after cannabis smoking. Naturalistic studies on tetrahydrocannabinol (THC) and CBD in blood samples are, however, missing. This study aimed to investigate the relationship between THC- and CBD concentrations in blood samples among cannabis users, and to compare cannabinoid concentrations with the outcome of a clinical test of impairment (CTI) and between traffic accidents and non-accident driving under the influence of drugs (DUID)-cases. Assessment of THC- and CBD contents in cannabis seizures was also included.

METHODS

THC- and CBD concentrations in blood samples from subjects apprehended in Norway from April 2013-April 2015 were included (n=6134). A CTI result was compared with analytical findings in cases where only THC and/or CBD were detected (n=705). THC- and CBD content was measured in 41 cannabis seizures.

RESULTS

Among THC-positive blood samples, 76% also tested positive for CBD. There was a strong correlation between THC- and CBD concentrations in blood samples (Pearson's r=0.714, p<0.0005). Subjects judged as impaired by a CTI had significantly higher THC- (p<0.001) and CBD (p=0.008) concentrations compared with not impaired subjects, but after multivariate analyses, impairment could only be related to THC concentration (p=0.004). Analyzing seizures revealed THC/CBD ratios of 2:1 for hashish and 200:1 for marijuana.

CONCLUSIONS

More than ¾ of the blood samples testing positive for THC, among subjects apprehended in Norway, also tested positive for CBD, suggesting frequent consumption of high CBD cannabis products. The simultaneous presence of CBD in blood does, however, not appear to affect THC-induced impairment on a CTI. Seizure sample analysis did not reveal high potency cannabis products, and while CBD content appeared high in hashish, it was almost absent in marijuana.

Impairment due to alcohol, tetrahydrocannabinol, and benzodiazepines in impaired drivers compared to experimental studies

OBJECTIVE

In some countries, per se laws for other drugs than alcohol are used to judge drunk and drugged drivers. These blood concentration limits are often derived from experimental studies on traffic relevant behavior of healthy volunteers. Knowledge about how results from experimental studies could be transferred to a real-life setting is missing. The aim of this study was to compare impairment seen in experimental studies to the impairment seen at equivalent concentrations in apprehended drunk and drugged drivers.

METHODS

Results from previously performed meta-analyses of experimental studies regarding impairment from alcohol, tetrahydrocannabinol (THC), and benzodiazepines were compared to impairment in apprehended drunk and drugged drivers as judged by a clinical test of impairment. Both experimental studies and real-life cases were divided into 4 groups according to increasing blood drug concentration intervals. The percentage of impaired test results in experimental studies was compared to the percentage of impaired subjects among drivers within the same blood drug concentration window.

RESULTS

For ethanol, the percentage of impaired drivers (n = 1,223) increased from 59% in the lowest drug concentration group to 95% in the highest drug concentration group, compared to 7 and 72% in the respective groups in experimental studies. For THC, the percentage of impaired drivers (n = 950) increased from 42 to 58%, the corresponding numbers being 11 and 42% for experimental studies. For benzodiazepines, the percentage of impaired drivers (n = 245) increased from 46 to 76%, the corresponding numbers being 16 and 60% for experimental studies. The increased odds ratio for impairment between 2 concentration groups was comparable for experimental studies and impaired drivers.

CONCLUSIONS

Fewer test results indicated impairment in experimental studies compared to impaired drivers in real life when influenced by similar blood concentrations of either ethanol, THC, or benzodiazepines. In addition, a comparable relationship between drug concentration and impairment was seen for both experimental studies and real-life cases. We believe that the present study strengthens the background for using experimental studies to establish fixed concentration limits for drunk and drugged drivers, but experimental studies in an impaired driver population could further expand our knowledge.

Effects of tetrahydrocannabinol on glucose uptake in the rat brain

Δ⁹-Tetrahydrocannabinol (THC) is the psychoactive component of the plant Cannabis sativa and acts as a partial agonist at cannabinoid type 1 and type 2 receptors in the brain. The goal of this study was to assess the effect of THC on the cerebral glucose uptake in the rat brain. 21 male Sprague Dawley rats (12-13 w) were examined and received five different doses of THC ranging from 0.01 to 1 mg/kg. For data acquisition a Focus 120 small animal PET scanner was used and 24.1-28.0 MBq of [¹⁸F]-fluoro-2-deoxy-d-glucose were injected. The data were acquired for 70 min and arterial blood samples were collected throughout the scan. THC, THC-OH and THC-COOH were determined at 55 min p.i. Nine volumes of interest were defined, and the cerebral glucose uptake was calculated for each brain region. Low blood THC levels of < 1 ng/ml (injected dose: ≤ 0.01 mg/kg) corresponded to an increased glucose uptake (6-30 %), particularly in the hypothalamus (p = 0.007), while blood THC levels > 10 ng/ml (injected dose: ≥ 0.05 mg/kg) coincided with a decreased glucose uptake (-2 to -22 %), especially in the cerebellar cortex (p = 0.008). The effective concentration in this region was estimated 2.4 ng/ml. This glucose PET study showed that stimulation of CB1 receptors by THC affects the glucose uptake in the rat brain, whereby the effect of THC is regionally different and dependent on dose - an effect that may be of relevance in behavioural studies.

Evaluation of divided attention psychophysical task performance and effects on pupil sizes following smoked, vaporized and oral cannabis administration

Establishing science-based driving per se blood Δ⁹ -tetrahydrocannabinol (THC) limits is challenging, in part because of prolonged THC detection in chronic, frequent users. Therefore, documenting observable signs of impairment is important for driving under the influence of drugs. We evaluated frequent and occasional cannabis smokers' performance on the modified Romberg balance, one leg stand (OLS), and walk and turn (WAT) tasks, and pupil size effects following controlled placebo (0.001% THC), smoked, vaporized and oral (6.9% [~50.4 mg] THC) cannabis administration. Significant effects following inhaled doses were not observed due to delayed tasks administration 1.5 and 3.5 h post-dose, but significant impairment was observed after oral dosing (blood THC concentrations peaked 1.5-3.5 h post-dose). Occasional smokers' odds of exhibiting ≥2 clues on the OLS or WAT following oral dosing were 6.4 (95% CI 2.3-18.4) times higher than after placebo, with THC and 11-hydroxy-THC blood concentrations individually producing odds ratios of 1.3 (1.1-1.5) and 1.5 (1.3-1.8) for impairment in these tasks, respectively. Pupil sizes after oral dosing under the direct lighting condition were significantly larger than after placebo by mean (SE, 95% CI) 0.4 (0.1, 0.2-0.6) mm at 1.5 h and 0.5 (0.2, 0.2-0.8) mm at 3.5 h among all participants. Oral cannabis administration impaired occasional cannabis users' performance on the OLS and WAT tasks compared to placebo, supporting other reports showing these tasks are sensitive to cannabis-related impairment. Occasional smokers' impairment was related to blood THC and 11-hydroxy-THC concentrations. These are important public health policy findings as consumption of edible cannabis products increases. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

Conversion of Cannabidiol Following Oral Administration: Authors' Response to Grotenhermen et al. DOI: 10.1089/can.2016.0036

In a commentary, Grotenhermen, Russo, and Zuardi questioned not only the clinical relevance but also the conclusions of a recently published study by Merrick et al. on the conversion of cannabidiol (CBD) to delta-8 and delta-9-tetrahydrocannabinol (THC) in simulated gastric fluid. In response, this article aims to provide a thorough review of the in vitro and in vivo studies of gastric CBD conversion as well as potential consequences resulting from such conversion. Findings highlight (1) consistent evidence over the past half century of gastric conversion of CBD, (2) evidence from human studies, indicating the importance of testing for THC metabolites as well as a number of other cannabinoids in the detection of such conversion, and (3) THC-like effects after administration of oral CBD in humans that may not only stem from CBD's conversion to THC, but also its conversion to 9α-hydroxy-hexahydrocannabinol and 8α-hydroxy-iso-hexahydrocannabinol. These findings, coupled with a number of limitations in the existing literature, point to the need for large-scale human studies, specifically designed to explore gastric conversion and potential THC-like side effects after oral administration of CBD.

Free and Glucuronide Whole Blood Cannabinoids' Pharmacokinetics after Controlled Smoked, Vaporized, and Oral Cannabis Administration in Frequent and Occasional Cannabis Users: Identification of Recent Cannabis Intake

BACKGROUND

There is increasing interest in markers of recent cannabis use because following frequent cannabis intake, Δ9-tetrahydrocannabinol (THC) may be detected in blood for up to 30 days. The minor cannabinoids cannabidiol, cannabinol (CBN), and THC-glucuronide were previously detected for ≤2.1 h in frequent and occasional smokers' blood after cannabis smoking. Cannabigerol (CBG), Δ9-tetrahydrocannabivarin (THCV), and 11-nor-9-carboxy-THCV might also be recent use markers, but their blood pharmacokinetics have not been investigated. Additionally, while smoking is the most common administration route, vaporization and edibles are frequently used.

METHODS

We characterized blood pharmacokinetics of THC, its phase I and phase II glucuronide metabolites, and minor cannabinoids in occasional and frequent cannabis smokers for 54 (occasional) and 72 (frequent) hours after controlled smoked, vaporized, and oral cannabis administration.

RESULTS

Few differences were observed between smoked and vaporized blood cannabinoid pharmacokinetics, while significantly greater 11-nor-9-carboxy-THC (THCCOOH) and THCCOOH-glucuronide concentrations occurred following oral cannabis. CBG and CBN were frequently identified after inhalation routes with short detection windows, but not detected following oral dosing. Implementation of a combined THC ≥5 μg/L plus THCCOOH/11-hydroxy-THC ratio &lt;20 cutoff produced detection windows &lt;8 h after all routes for frequent smokers; no occasional smoker was positive 1.5 h or 12 h following inhaled or oral cannabis, respectively.

CONCLUSIONS

Vaporization and smoking provide comparable cannabinoid delivery. CBG and CBN are recent-use cannabis markers after cannabis inhalation, but their absence does not exclude recent use. Multiple, complimentary criteria should be implemented in conjunction with impairment observations to improve interpretation of cannabinoid tests. Clinicaltrials.gov Identifier: NCT02177513

Plasma Cannabinoid Pharmacokinetics After Controlled Smoking and Ad libitum Cannabis Smoking in Chronic Frequent Users

More Americans are dependent on cannabis than any other illicit drug. The main analytes for cannabis testing include the primary psychoactive constituent, Δ(9)-tetrahydrocannabinol (THC), equipotent 11-hydroxy-THC (11-OH-THC) and inactive 11-nor-9-carboxy-THC (THCCOOH). Eleven adult chronic frequent cannabis smokers resided on a closed research unit with unlimited access to 5.9% THC cannabis cigarettes from 12:00 to 23:00 during two ad libitum smoking phases, followed by a 5-day abstinence period in seven participants. A single cigarette was smoked under controlled topography on the last day of the smoking and abstinence phases. Plasma cannabinoids were quantified by two-dimensional gas chromatography-mass spectrometry. Median plasma maximum concentrations (Cmax) were 28.3 (THC), 3.9 (11-OH-THC) and 47.0 μg/L (THCCOOH) 0.5 h after controlled single cannabis smoking. Median Cmax 0.2-0.5 h after ad libitum smoking was higher for all analytes: 83.5 (THC), 14.2 (11-OH-THC) and 155 μg/L (THCCOOH). All 11 participants' plasma samples were THC and THCCOOH-positive, 58.3% had THC ≥5 μg/L and 79.2% were 11-OH-THC-positive 8.1-14 h after last cannabis smoking. Cannabinoid detection rates in seven participants 106-112 h (4-5 days) after last smoking were 92.9 (THC), 35.7 (11-OH-THC) and 100% (THCCOOH), with limits of quantification of 0.5 μg/L for THC and THCCOOH, and 1.0 μg/L for 11-OH-THC. These data greatly expand prior research findings on cannabinoid excretion profiles in chronic frequent cannabis smokers during ad libitum smoking. Smoking multiple cannabis cigarettes led to higher Cmax and AUC compared with smoking a single cigarette. The chronic frequent cannabis smokers exhibited extended detection windows for plasma cannabinoids, reflecting a large cannabinoid body burden.

A Judicial Perspective on Expert Testimony in Marijuana Driving Cases

The decriminalization of marijuana and propagation of marijuana prescribed for medical reasons have resulted in an increase in driving while under the influence of marijuana. Currently, the legal definition of marijuana driving impairment varies by state across the United States. Expert witnesses such as drug recognition experts and medical toxicologists are needed during a discovery to educate attorneys and during a testimony to educate judges and juries. These proceedings provide an overview of the US case law about driving impairment, the current status of the legal thresholds used in the courts for the admission of the medical toxicologist as an expert witness in marijuana driving and related cases, and provides an understanding of evolving issues surrounding the admissibility of their scientific opinion testimony.

Small Molecule Detection in Saliva Facilitates Portable Tests of Marijuana Abuse

As medical and recreational use of cannabis, or marijuana, becomes more prevalent, law enforcement needs a tool to evaluate whether drivers are operating vehicles under the influence of cannabis, specifically the psychoactive substance, tetrahydrocannabinol (THC). However, the cutoff concentration of THC that causes impairment is still controversial, and current on-site screening tools are not sensitive enough to detect trace amounts of THC in oral fluids. Here we present a novel sensing platform that employs giant magnetoresistive (GMR) biosensors integrated with a portable reader system and smartphone to detect THC in saliva using competitive assays. With a simple saliva collection scheme, we have optimized the assay to measure THC in the range from 0 to 50 ng/mL, covering most cutoff values proposed in previous studies. This work facilitates on-site screening for THC and shows potential for testing of other small molecule drugs and analytes in point-of-care (POC) settings.

Effect of Blood Collection Time on Measured Δ9-Tetrahydrocannabinol Concentrations: Implications for Driving Interpretation and Drug Policy

BACKGROUND

In driving-under-the-influence cases, blood typically is collected approximately 1.5-4 h after an incident, with unknown last intake time. This complicates blood Δ(9)-tetrahydrocannabinol (THC) interpretation, owing to rapidly decreasing concentrations immediately after inhalation. We evaluated how decreases in blood THC concentration before collection may affect interpretation of toxicological results.

METHODS

Adult cannabis smokers (≥1×/3 months, ≤3 days/week) drank placebo or low-dose alcohol (approximately 0.065% peak breath alcohol concentration) 10 min before inhaling 500 mg placebo, 2.9%, or 6.7% vaporized THC (within-individuals), then took simulated drives 0.5-1.3 h postdose. Blood THC concentrations were determined before and up to 8.3 h postdose (limit of quantification 1 μg/L).

RESULTS

In 18 participants, observed Cmax (at 0.17 h) for active (2.9 or 6.7% THC) cannabis were [median (range)] 38.2 μg/L (11.4-137) without alcohol and 47.9 μg/L (13.0-210) with alcohol. THC Cmax concentration decreased 73.5% (3.3%-89.5%) without alcohol and 75.1% (11.5%-85.4%) with alcohol in the first half-hour after active cannabis and 90.3% (76.1%-100%) and 91.3% (53.8%-97.0%), respectively, by 1.4 h postdose. When residual THC (from previous self-administration) was present, concentrations rapidly decreased to preinhalation baselines and fluctuated around them. During-drive THC concentrations previously associated with impairment (≥8.2 μg/L) decreased to median <5 μg/L by 3.3 h postdose and <2 μg/L by 4.8 h postdose; only 1 participant had THC ≥5 μg/L after 3.3 h.

CONCLUSIONS

Forensic blood THC concentrations may be lower than common per se cutoffs despite greatly exceeding them while driving. Concentrations during driving cannot be back-extrapolated because of unknown time after intake and interindividual variability in rates of decrease.

Cannabis and tolerance: acute drug impairment as a function of cannabis use history

Cannabis use history as predictor of neurocognitive response to cannabis intoxication remains subject to scientific and policy debates. The present study assessed the influence of cannabis on neurocognition in cannabis users whose cannabis use history ranged from infrequent to daily use. Drug users (N = 122) received acute doses of cannabis (300 μg/kg THC), cocaine HCl (300 mg) and placebo. Cocaine served as active control for demonstrating neurocognitive test sensitivity. Executive function, impulse control, attention, psychomotor function and subjective intoxication were significantly worse after cannabis administration relative to placebo. Cocaine improved psychomotor function and attention, impaired impulse control and increased feelings of intoxication. Acute effects of cannabis and cocaine on neurocognitive performance were similar across cannabis users irrespective of their cannabis use history. Absence of tolerance implies that that frequent cannabis use and intoxication can be expected to interfere with neurocognitive performance in many daily environments such as school, work or traffic.

Acute and Chronic Effects of Cannabinoids on Human Cognition-A Systematic Review

Cannabis use has been associated with impaired cognition during acute intoxication as well as in the unintoxicated state in long-term users. However, the evidence has been mixed and contested, and no systematic reviews of the literature on neuropsychological task-based measures of cognition have been conducted in an attempt to synthesize the findings. We systematically review the empirical research published in the past decade (from January 2004 to February 2015) on acute and chronic effects of cannabis and cannabinoids and on persistence or recovery after abstinence. We summarize the findings into the major categories of the cognitive domains investigated, considering sample characteristics and associations with various cannabis use parameters. Verbal learning and memory and attention are most consistently impaired by acute and chronic exposure to cannabis. Psychomotor function is most affected during acute intoxication, with some evidence for persistence in chronic users and after cessation of use. Impaired verbal memory, attention, and some executive functions may persist after prolonged abstinence, but persistence or recovery across all cognitive domains remains underresearched. Associations between poorer performance and a range of cannabis use parameters, including a younger age of onset, are frequently reported. Little further evidence has emerged for the development of tolerance to the acutely impairing effects of cannabis. Evidence for potential protection from harmful effects by cannabidiol continues to increase but is not definitive. In light of increasing trends toward legalization of cannabis, the knowledge gained from this body of research needs to be incorporated into strategies to minimize harm.